1. Field of the Invention
The present invention relates generally to an electronic musical instrument of the type for synthesizing a musical sound through calculating means using a discrete Fourier transfer, and more particularly to an electronic musical instrument in which the level of an input value is divided into a plurality of blocks and functions corresponding to the blocks are subjected to data conversion and then are selectively combined to obtain a variety of filter characteristics.
2. Description of the Prior Art
Conventional electronic musical instruments mostly employ a system of synthesizing a musical sound through a discrete Fourier transfer based on harmonic coefficients selectively read out from a memory. In this case, in order to obtain filter characteristics for introducing variations in the tone of the musical sound, it is customary to synthesize the musical sound by reading out digital level information of a waveshape prestored in a memory accordance with frequency and then multiplying it by a harmonic coefficient. With this method, however, the quantity of level information prestored in the memory is enormous. As a solution to this problem, it has been proposed to represent the waveshape by a small amount of information; in general, however processing becomes complicated corresponding to the reduction of information. Thus, in order to obtain many kinds of filter characteristics, the electronic musical instrument inevitably becomes complex in structure.